The present invention is related to a grinder, and more particularly to a grinder in which the grinding disc can be easily replaced without using any tool. In addition, when replacing the grinding disc, the grinder is prevented from being powered on so as to avoid mis-operation.
A conventional grinder has a grinding disc mounted on a bottom section of the grinder. The grinding disc has a central threaded rod screwed with a rotary shaft of the grinder. The rotary shaft serves to drive the grinding disc to grind a work piece.
In operation, it is necessary to frequently replace the grinding disc. Conventionally, when replacing the grinding disc, a flat wrench is extended into the bottom of the grinder for clogging the rotary shaft of the grinder. Under such circumstance, the grinding disc can be unscrewed from the rotary shaft and taken off. Similarly, when installing the grinding disc, it is also necessary to fix the rotary shaft. Such replacement operation is quite inconvenient and time-consuming.
This inventor has developed various grinder structures in which the rotary shaft can be easily fixed for replacing the grinding disc without using any tool. However, it often takes place that when replacing the disc, the grinder is incautiously powered on. Under such circumstance, the components of the grinder may be damaged.